<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
    <title>Title</title>
    <style>
      .d1{
        width: 200px;
        height: 200px;
        background-color: #0aa1ed;
        border: 5px solid red;
        border-top: 5px double yellow;
        border-radius: 100px;
      }
      .d2{
          width: 200px;
          height: 200px;
          background-color: pink;
          /*默认加边框与内间距都会让元素变大*/
          border: 5px solid magenta;
          padding-left: 50px;
          padding-top: 50px;
          /*外间距不属于元素本身的大小,但是外间距会占用页面的布局空间*/
          margin: 50px;
          /*无论是加内间距还是边框,大小都不会改变,都算在预设的宽高之内*/
          box-sizing: border-box;
      }
      .s2{
          padding: 50px;
          background-color: red;
      }
    </style>
</head>
<body>
  <div class="d1">
  </div>
  <div class="d2">内间距测试</div>
  <span>span1</span><span class="s2">span2</span><span>span3</span>
    <h1>hahahahahhahahahahaaaaaaaaaaaaaa</h1>
</body>
</html>